RNA primer is defined as which of the following?

RNA primer is defined as which of the following?

• A. Short RNA segment used to initiate synthesis of a new strand of DNA during replication
• B. Protein that binds to telomeres
• C. Enzyme that unwinds DNA
• D. Termination signal in transcription

Answer: (A)

DNA polymerases can’t start a new strand from scratch; they can only extend an existing end with a 3' hydroxyl. An RNA primer provides that starting point. It’s a short RNA segment made by primase that gets laid down on the template strand to initiate DNA synthesis. On the leading strand, synthesis begins with a single primer, while on the lagging strand primers are needed for each Okazaki fragment. Once DNA synthesis starts, the RNA primer is removed and replaced with DNA. The concept you’re testing is that the RNA primer’s role is to supply the initial 3' end for polymerase activity. The other descriptions refer to different molecules or functions (a telomere-binding protein, a helicase, or a transcription termination signal) and do not describe primers.

DNA polymerases can’t start a new strand from scratch; they can only extend an existing end with a 3' hydroxyl. An RNA primer provides that starting point. It’s a short RNA segment made by primase that gets laid down on the template strand to initiate DNA synthesis. On the leading strand, synthesis begins with a single primer, while on the lagging strand primers are needed for each Okazaki fragment. Once DNA synthesis starts, the RNA primer is removed and replaced with DNA. The concept you’re testing is that the RNA primer’s role is to supply the initial 3' end for polymerase activity.

The other descriptions refer to different molecules or functions (a telomere-binding protein, a helicase, or a transcription termination signal) and do not describe primers.